The present invention relates to a self-starting single-phase synchronous motor, more especially a miniature motor, having a coil located inside a permanently magnetized bell-shaped rotor, the core of the coil being connected on both sides with stator components one of which is located between the and rotor, and the other being located outside the rotor.
Such a motor is known, e.g. from the German Offenlegungsschrift No. 2,254,897, and even though this motor has the advantage of the length of winding in the internally located coil being small and therefore the requirement in copper and the copper losses being accordingly low, the motor is not very efficient nor does it have a particularly high performance because distinct poles are provided only inside the rotor. It has also been found that this known motor, in which the rotor is securely mounted on the shaft, has no favorable starting characteristics.
It is an object of the present invention to provide a self-starting single-phase synchronous motor which has a high degree of efficiency and a high specific output and optimum starting characteristics under all conceivable load conditions.